It might also be a good excuse to upgrade. You could sell the 75-300 for what ever you can get, and then buy a used 55-250 IS for about $150. The 55-250 is optically better AND had image stabilization.

Re: broken filter threads

I'd either super glue the hood in place or follow Mike's advice and upgrade. It's not worth repairing. I saw a refurbished 55-250 for just over $100 the other day. Canon's website is down otherwise I'd link it. Refurbished to original specs, with warranty, for a much better lens. There's no